Using rain water

[Orchid126]

Also remember that rain water has no fertilizers in it. You will have to supplement it with some micro and macro additive.

[Ray]

A word to the wise: whenever you use a pure water supply - rainwater, RO, DI, distilled, etc - you cannot just arbitrarily use an "over the counter" fertilizer, or the pH will be WAAAY too low. You'll either have to adjust it, or use a formula designed to control that pH in pure water, like the MSU RO, or K-Lite formula.

[Wild Orchid]

Originally Posted by silken

I use it on all my orchids and the Phrags and Masdies particularly prefer it. But as mentioned above, it depends on where you live and also what kind of roof it is coming off of, pollution levels etc. Since your outdoor plants like it, I would use it.

I use to collect rain water but the challenge I encoutered was that it's always icy cold - mainly in the winter months when we get most of the rains in Vancouver. So with that, one has to figure out how to warm it up in large quantities.
And then we might not get that much of rain during the summer, so we're back to tap water anyway... So I figured, the 'kids' will have to live with what I have to offer them.
(Supposely, the BC water is one of the "cleanest". I don't know.)

Lilia

[goodgollymissmolly]

Originally Posted by james mickelso

Rain water is great to use on orchids or any other plants. But..... it can harbor fungus and bacteria as well as viruses. Chances are small but it can. I would use it in a heartbeat but then again all my orchids are rescues. Depending on where you live the pH can be high, low, or everywhere in between. That can also be good....or bad.

Having been burned repeatedly by attempting to reason with those on the internet who deny science and apparently lack even a minor dose of common sense, I am intimidated by trying again, but here goes.

Suggesting that rain water harbors pathogens harmful to plants (and especially viruses) ignores the rational fact that plants grow in the wild and always (100% of the time) get their water from rainwater or its aged residue in ponds, rivers, lakes, etc. Have we become so civilized that we believe plants originated in greenhouses, window sills and in basements under lights?

I've posted a link at the bottom regarding this and it is substantiated by other studies like the recent article in the International Phalaenopsis magazine. Bottom line...orchids in the wild are not infested with viruses which eliminates rain water and its derivatives as a culprit in virus transmission. Bacterial and fungal infections do not occur from rain water either. However the foliage wet with rainwater might allow those naturally occurring pathogens to infest the plant. Can you blame the rain water for that?

Cultivated orchids and other cultivated plants do have viruses. So who is to blame? Obviously man is the transmission source. Some blame dirty tools but I have never seen a tool flying around my greenhouse on its own. My tools at least only are propelled into action by me.

I realize that I infuriate the internet population when I say it is the biggest source of misinformation and constantly repeated misinformation ever conceived by mankind, but it is. If you want to actually learn something buy a book which is almost always peer reviewed before publication. Anybody can put anything on the internet, most of it totally garbage.

http://www.apsnet.org/publications/P...80n10_1160.pdf

[Ray]

In my opinion, neither this nor your quoted information are totally correct, incorrect, or complete.

Water certainly can harbor viruses, bacteria, and fungi. However, they may not be the same viruses, bacteria and fungi that infect orchids. Most such infectious critters are fairly host-specific, and while they may survive outside of that host, it is often for a limited time.

Claiming that water plays no role in spreading of pathogens, however, is pure folly.

[Leafmite]

Thanks for reminding everyone to use a complete fertilizer. I always used the rainwater from my goldfish pond (later, goldfish tub) and my plants and orchids thrived Two years ago, we had plenty of rain so I didn't need the fish water and just used my fertilizer...the result was blackened new growths that spread as black rot (calcium deficiency, weak growths). Once I corrected this, no further trouble. I now use an MSU fertilizer, very weak, with some additions (I try to avoid salts building up) and my orchids are again thriving. Experience can be a nasty but great teacher.

[goodgollymissmolly]

"Claiming that water plays no role in spreading of pathogens, however, is pure folly."

Not sure what you were reading, but it sure wasn't what I wrote. We were discussing rain and I specifically said rain and discussed plants in the wild. Those orchids through a number of studies don't have viruses. If you could get viruses from rain then they would have them. No doubt that allowing water (rain or other) to drain from an infected cultivated plant onto another can spread virus and frequently does. The virus did not come from water, it came from an infected plant. Apparently that does not happen in the wild where there are no infected plants.

I've no problem with your debating, just read what I said first rather than change the context of my comments.

[ALToronto]

Rainwater in the tropics is not the same rainwater that is collected in cities. I have rain barrels, but I don't use the water in them - too much crud from the roof and gutters turns it into a fungus-breeding swamp. I wish we could collect each raindrop directly as it falls from the sky, but to get any appreciable quantity of water here in the cold north, where we don't get 90-minute monsoons every day, we have to have the rain fall on some large surface first - such as a roof.

Roofs are usually covered with asphalt shingles (which contribute some nasty chemical crud), raccoon and squirrel 'deposits' - and those from meat-eating animals are really not good for plants - and decaying leaves. Leaves from city trees are often infected with fungi and viruses, and then these organisms are transferred to the collected rain water. So no, not all rain is created equal, and the rain that waters orchids in the wild is not the same rain that we in the cities collect in our rain barrels.

[Brooke]

Do trees have the same viruses as orchids? I know impatiens and tomato plants carry a virus that will infect orchids but I've never seen a report on trees being dangerous.

Brooke

[Ray]

Good golly....it was really early, and I may not have been caffeinated enough. My apologies.